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2020 Volume 36 Issue 3
2020, 36(3): 393-405
doi: 10.11862/CJIC.2020.062
Abstract:
Porous silicon nanomaterials hold great promise in the fields of drug therapy, sensors and energy storage and conversion due to their high specific surfaces areas and tunable physicochemical properties. Especially in the area of high energy lithium ion batteries, porous silicon has attracted many concerns owning to the abundant pore channels, which will effectively releasing the huge stress that induced by the volume change and shorten the lithium ion transport distance. However, developing rapid and convenient methods for preparing structure tunable porous silicon still remain challenge. In recent years, some feasible strategies have been proposed and developed to synthesize porous silicon. Based on the recent developments, this review detailedly summarizes the current popular approaches that have been employed in the preparation of porous silicon, as well as the applications in high energy lithium ion batteries. Finally, some directions that can further promote the development of porous silicon have also been proposed.
Porous silicon nanomaterials hold great promise in the fields of drug therapy, sensors and energy storage and conversion due to their high specific surfaces areas and tunable physicochemical properties. Especially in the area of high energy lithium ion batteries, porous silicon has attracted many concerns owning to the abundant pore channels, which will effectively releasing the huge stress that induced by the volume change and shorten the lithium ion transport distance. However, developing rapid and convenient methods for preparing structure tunable porous silicon still remain challenge. In recent years, some feasible strategies have been proposed and developed to synthesize porous silicon. Based on the recent developments, this review detailedly summarizes the current popular approaches that have been employed in the preparation of porous silicon, as well as the applications in high energy lithium ion batteries. Finally, some directions that can further promote the development of porous silicon have also been proposed.
2020, 36(3): 406-414
doi: 10.11862/CJIC.2020.049
Abstract:
Synthesis of novel ferric cyanide hydrogen-bonding cage-like supramolecular crystal material (C3H5N2)3[Fe(CN)6]·2(18-crown-6)·2H2O (1) by solvent evaporation in methanol solution with imidazole, 18-crown-6 and ferric cyanide. The structure, thermal energy and electrical properties of the crystal were characterized by variable temperature X-ray diffraction single crystal diffraction, infrared spectroscopy, elemental analysis, thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and dielectric constant test. The space group of the crystal is P21/c, which belongs to the monoclinic system at low temperatures. The crystal structure shows that the cyano-iron complex, the water molecule and the imidazolium cation form a three-dimensional cage structure with iron atoms as the apex in the form of hydrogen bonds. This resulted in phase transition at around 250 K and stepped reversible dielectric anomalies in a range of 220~260 K. Temperature variation triggers the cage structure abrupt change, and at the same time causes dynamic oscillation of supramolecules within the framework of[Fe(CN)6]3-, thus induces the phase transition of crystal structure. The phase transition temperature interval of the crystal structure was accompanied with step-like change in dielectric physical properties. The dielectric constant was reversible and changed from 38 to 43 with temperature increasing from 220 to 280 K. Above 270 K, the sudden jump in dielectric is caused by water vapor.
Synthesis of novel ferric cyanide hydrogen-bonding cage-like supramolecular crystal material (C3H5N2)3[Fe(CN)6]·2(18-crown-6)·2H2O (1) by solvent evaporation in methanol solution with imidazole, 18-crown-6 and ferric cyanide. The structure, thermal energy and electrical properties of the crystal were characterized by variable temperature X-ray diffraction single crystal diffraction, infrared spectroscopy, elemental analysis, thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and dielectric constant test. The space group of the crystal is P21/c, which belongs to the monoclinic system at low temperatures. The crystal structure shows that the cyano-iron complex, the water molecule and the imidazolium cation form a three-dimensional cage structure with iron atoms as the apex in the form of hydrogen bonds. This resulted in phase transition at around 250 K and stepped reversible dielectric anomalies in a range of 220~260 K. Temperature variation triggers the cage structure abrupt change, and at the same time causes dynamic oscillation of supramolecules within the framework of[Fe(CN)6]3-, thus induces the phase transition of crystal structure. The phase transition temperature interval of the crystal structure was accompanied with step-like change in dielectric physical properties. The dielectric constant was reversible and changed from 38 to 43 with temperature increasing from 220 to 280 K. Above 270 K, the sudden jump in dielectric is caused by water vapor.
2020, 36(3): 415-420
doi: 10.11862/CJIC.2020.058
Abstract:
Three-dimensional (3D) porous carbon materials are successfully prepared by molten salt zinc-thermal method using sucrose as precursor and used as anode materials for potassium ion batteries. The prepared 3D porous carbon has a large number of interconnected channels, which can effectively alleviate the volume effect of the electrode during the charge-discharge cycling process, improve the infiltration of electrolyte to the electrode, shorten the diffusion path of K+. Therefore, it shows excellent cycle stability and rate performance. 3D porous carbon electrode delivers the specific capacity of 174.6 mAh·g-1 after 2 500 cycles at current density of 0.5 A·g-1 and 170 mAh·g-1 at a high rate of 4.4 A·g-1.
Three-dimensional (3D) porous carbon materials are successfully prepared by molten salt zinc-thermal method using sucrose as precursor and used as anode materials for potassium ion batteries. The prepared 3D porous carbon has a large number of interconnected channels, which can effectively alleviate the volume effect of the electrode during the charge-discharge cycling process, improve the infiltration of electrolyte to the electrode, shorten the diffusion path of K+. Therefore, it shows excellent cycle stability and rate performance. 3D porous carbon electrode delivers the specific capacity of 174.6 mAh·g-1 after 2 500 cycles at current density of 0.5 A·g-1 and 170 mAh·g-1 at a high rate of 4.4 A·g-1.
2020, 36(3): 421-425
doi: 10.11862/CJIC.2020.065
Abstract:
A composite of Prussian/manganese dioxide (PB/MnO2) was prepared. Characterization results showed that two materials were well composited. Electrochemical results showed that the composite possessed better electroactivity than PB. The sensor fabricated on the composite modified glassy carbon electrode (GCE) showed excellent response to the reduction of hydrogen peroxide (H2O2) with wide linear range, good stability, reproducibility and selectivity.
A composite of Prussian/manganese dioxide (PB/MnO2) was prepared. Characterization results showed that two materials were well composited. Electrochemical results showed that the composite possessed better electroactivity than PB. The sensor fabricated on the composite modified glassy carbon electrode (GCE) showed excellent response to the reduction of hydrogen peroxide (H2O2) with wide linear range, good stability, reproducibility and selectivity.
2020, 36(3): 426-434
doi: 10.11862/CJIC.2020.063
Abstract:
Photocatalytic synthesis of ammonia is a sustainable and energy-saving synthetic ammonia technology. Rich oxygen vacancies and heterostructures are important to increase the photocatalytic nitrogen to ammonia. We synthesized Fe2O3/ZnO nanocomposites by solvothermal method using ethylene glycol as the reducing agent. X-ray diffraction (XRD), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR), UV-Vis DRS, photoluminescence (PL) and photocurrent (PC) were used to characterize the Fe2O3/ZnO catalysts. The performance of photocatalytic synthesis of ammonia by Fe2O3/ZnO catalysts was tested at room temperature. The results show that heterostructure was formed between ZnO nanorods and Fe2O3 nanoparticles while abundant surface oxygen vacancies were produced over the Fe2O3/ZnO catalysts. Fe2O3 nanoparticles not only provide rich N2 chemical adsorption sites, but also promote the light absorption of ZnO in the visible region. The introduction of Fe2O3 reduces the concentration of bulk oxygen vacancies and inhibits the recombination of photogenerated electrons and holes. The 4%Fe2O3/ZnO catalyst exhibited enhanced photocatalytic nitrogen fixation efficiency with a NH3 rate of 2 059 μmol·L-1·g-1·h-1 with better stability. The high catalytic efficiency is attributed to the enhancement of visible light absorption, the activation of nitrogen molecules on surface oxygen vacancies and Fe3+ active sites, and the high separation efficiency of photogenerated electrons and holes.
Photocatalytic synthesis of ammonia is a sustainable and energy-saving synthetic ammonia technology. Rich oxygen vacancies and heterostructures are important to increase the photocatalytic nitrogen to ammonia. We synthesized Fe2O3/ZnO nanocomposites by solvothermal method using ethylene glycol as the reducing agent. X-ray diffraction (XRD), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR), UV-Vis DRS, photoluminescence (PL) and photocurrent (PC) were used to characterize the Fe2O3/ZnO catalysts. The performance of photocatalytic synthesis of ammonia by Fe2O3/ZnO catalysts was tested at room temperature. The results show that heterostructure was formed between ZnO nanorods and Fe2O3 nanoparticles while abundant surface oxygen vacancies were produced over the Fe2O3/ZnO catalysts. Fe2O3 nanoparticles not only provide rich N2 chemical adsorption sites, but also promote the light absorption of ZnO in the visible region. The introduction of Fe2O3 reduces the concentration of bulk oxygen vacancies and inhibits the recombination of photogenerated electrons and holes. The 4%Fe2O3/ZnO catalyst exhibited enhanced photocatalytic nitrogen fixation efficiency with a NH3 rate of 2 059 μmol·L-1·g-1·h-1 with better stability. The high catalytic efficiency is attributed to the enhancement of visible light absorption, the activation of nitrogen molecules on surface oxygen vacancies and Fe3+ active sites, and the high separation efficiency of photogenerated electrons and holes.
2020, 36(3): 435-442
doi: 10.11862/CJIC.2020.064
Abstract:
The mechanism of catalytic hydrolysis cleavage of RNA phosphodiester analogue 2-(hydroxypropyl)-4-nitrophenyl phosphate (HpPNP) by corrole manganese(Ⅲ) complex were studied by density functional theory B3LYP method. And the influence of the reaction energy barrier for the property and number of the meso-substituents were also investigated. The results show that the fracture reaction is carried out by special base catalysis (SBC) mechanism, and the corrole manganese(Ⅲ) complex forms a unique transition state structure of double hydrogen bond and double coordination with HpPNP, and then the product is formed after the P-O bond is broken. Corrole manganese(Ⅲ) complexes with electron-absorbing substituents can reduce the energy barrier by 4% to 34% compared with that without catalyst. The electron absorbing substituent effect in corrole manganese(Ⅲ) complexes can significantly reduce the reaction energy barrier and promote the hydrolysis fracture reaction.
The mechanism of catalytic hydrolysis cleavage of RNA phosphodiester analogue 2-(hydroxypropyl)-4-nitrophenyl phosphate (HpPNP) by corrole manganese(Ⅲ) complex were studied by density functional theory B3LYP method. And the influence of the reaction energy barrier for the property and number of the meso-substituents were also investigated. The results show that the fracture reaction is carried out by special base catalysis (SBC) mechanism, and the corrole manganese(Ⅲ) complex forms a unique transition state structure of double hydrogen bond and double coordination with HpPNP, and then the product is formed after the P-O bond is broken. Corrole manganese(Ⅲ) complexes with electron-absorbing substituents can reduce the energy barrier by 4% to 34% compared with that without catalyst. The electron absorbing substituent effect in corrole manganese(Ⅲ) complexes can significantly reduce the reaction energy barrier and promote the hydrolysis fracture reaction.
2020, 36(3): 443-450
doi: 10.11862/CJIC.2020.061
Abstract:
Carbon quantum dots doped octahedral bipyramids TiO2 with high exposed (101) reactive facets and carbon quantum dots doped nanosheets TiO2 with high exposed (001) reactive facets were successfully fabricated by facile solvothermal process. The catalysts were characterized using TEM, XRD and XPS measurements. They confirm that the carbon quantum dots were uniformly integrated to TiO2. The catalytic activity of the as-prepared catalysts in degradation of rhodamine B in aqueous solution under visible light irradiation (λ ≥ 400 nm) was systematically investigated. The experiments show that the doping of carbon quantum dots in TiO2 can substantially improve the photo degradation efficiency relative to pure TiO2, both for octahedral bipyramids TiO2 and nanosheets TiO2. Generally, the photodegradation efficiency of (101) facet exposed octahedral bipyramids TiO2 is prevailing over that of (001) facet exposed nanosheets TiO2.
Carbon quantum dots doped octahedral bipyramids TiO2 with high exposed (101) reactive facets and carbon quantum dots doped nanosheets TiO2 with high exposed (001) reactive facets were successfully fabricated by facile solvothermal process. The catalysts were characterized using TEM, XRD and XPS measurements. They confirm that the carbon quantum dots were uniformly integrated to TiO2. The catalytic activity of the as-prepared catalysts in degradation of rhodamine B in aqueous solution under visible light irradiation (λ ≥ 400 nm) was systematically investigated. The experiments show that the doping of carbon quantum dots in TiO2 can substantially improve the photo degradation efficiency relative to pure TiO2, both for octahedral bipyramids TiO2 and nanosheets TiO2. Generally, the photodegradation efficiency of (101) facet exposed octahedral bipyramids TiO2 is prevailing over that of (001) facet exposed nanosheets TiO2.
2020, 36(3): 451-457
doi: 10.11862/CJIC.2020.057
Abstract:
A series of layered CuyFe6-yAl2Ox catalysts were prepared via the controlled calcination of CuyFe6-yAl2-LDH and applied in the Fenton degradation reaction of high concentrated rhodamine B (RhB, 450 mg·L-1) under neutral conditions at room temperature. It was found that Cu5FeAl2Ox-500, which was prepared at a calcination temperature of 500℃, was most active for the degradation RhB. Over Cu5FeAl2Ox-500 catalyst (with 0.1%(w/w) loading), RhB could be completely degraded within 150 min, and the chemical oxygen demand (COD) removal efficiency reached 86.5%. The characterizations indicated that both Cu and Fe have a good synergistic effect for the degradation reaction as the formation of CuFe2O4. At the same time, the catalyst with larger specific surface area and bigger pore volume was also favorable for the degradation of RhB and COD removal. It was also confirmed that Cu5FeAl2Ox-500 catalyst was capable for the degradation of a variety of pollutants.
A series of layered CuyFe6-yAl2Ox catalysts were prepared via the controlled calcination of CuyFe6-yAl2-LDH and applied in the Fenton degradation reaction of high concentrated rhodamine B (RhB, 450 mg·L-1) under neutral conditions at room temperature. It was found that Cu5FeAl2Ox-500, which was prepared at a calcination temperature of 500℃, was most active for the degradation RhB. Over Cu5FeAl2Ox-500 catalyst (with 0.1%(w/w) loading), RhB could be completely degraded within 150 min, and the chemical oxygen demand (COD) removal efficiency reached 86.5%. The characterizations indicated that both Cu and Fe have a good synergistic effect for the degradation reaction as the formation of CuFe2O4. At the same time, the catalyst with larger specific surface area and bigger pore volume was also favorable for the degradation of RhB and COD removal. It was also confirmed that Cu5FeAl2Ox-500 catalyst was capable for the degradation of a variety of pollutants.
2020, 36(3): 458-466
doi: 10.11862/CJIC.2020.048
Abstract:
Urchin-like MnO2 microspheres with three different crystalline phases (α, γ and β) were prepared by hydrothermal and calcination methods, and the oxygen reduction reaction (ORR) properties were systematically studied. The results of electrocatalytic tests indicated that the ORR activities of these three MnO2 microspheres followed a sequence:α-MnO2 > γ-MnO2 > β-MnO2. The α-MnO2 sample exhibited the best electrocatalytic performance towards ORR with an onset potential of 0.92 V (vs RHE) and a potential of 0.77 V (vs RHE) at -3 mA·cm-2. The superior ORR activity of urchin-like α-MnO2 microspheres was mainly related to the larger amount of Mn3+, more surface oxygen vacancies and better conductivity. Specially, the Mn3+ could promote the dissociation of O-O bond and conduce to one-electron transfer to adsorbed oxygen, thereby accelerating the exchange of O22-/OH- that regarded as the rate-limiting step of the ORR.
Urchin-like MnO2 microspheres with three different crystalline phases (α, γ and β) were prepared by hydrothermal and calcination methods, and the oxygen reduction reaction (ORR) properties were systematically studied. The results of electrocatalytic tests indicated that the ORR activities of these three MnO2 microspheres followed a sequence:α-MnO2 > γ-MnO2 > β-MnO2. The α-MnO2 sample exhibited the best electrocatalytic performance towards ORR with an onset potential of 0.92 V (vs RHE) and a potential of 0.77 V (vs RHE) at -3 mA·cm-2. The superior ORR activity of urchin-like α-MnO2 microspheres was mainly related to the larger amount of Mn3+, more surface oxygen vacancies and better conductivity. Specially, the Mn3+ could promote the dissociation of O-O bond and conduce to one-electron transfer to adsorbed oxygen, thereby accelerating the exchange of O22-/OH- that regarded as the rate-limiting step of the ORR.
2020, 36(3): 467-474
doi: 10.11862/CJIC.2020.047
Abstract:
A kind of cheap carbon nanotube-based double transition metal nitrides Co3W3N/CNTs composite was prepared by hydrothermal and subsequent heat treatment under ammonia. By adjusting the proportion the of pre oxidation of CNTs and precursor CoWO4 and ammonia heat treatment temperature, the Co3W3N in uniform load on the surface of the CNTs. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) test results showed that the catalyst particles evenly dispersed on the surface of CNTs, due to oxidation CNTs for the good dispersion growth of precursor. The Co3W3N particle size on the CNTs was about 20 nm, which was significantly smaller than that of unsupported Co3W3N (100 nm). The electrochemical tests was carried out in a N2 saturated 0.01 mol·L-1 H2SO4 solution under different potential, and the material achieved the highest ammonia production rate and Faraday efficiency at -0.3 V, which reached approximately 12.73 μg·h-1·cm-2 and 13.59%, respectively. Under the same conditions, the ammonia production rate and Faraday efficiency of pure phase Co3W3N were only 1.08 μg·h-1·cm-2 and 1.76%. The Co3W3N/CNTs sample showed excellent NRR (nitrogen reduction reaction) performance because of the Co3W3N as the active site and the synergistic effect of Co3W3N and CNTs.
A kind of cheap carbon nanotube-based double transition metal nitrides Co3W3N/CNTs composite was prepared by hydrothermal and subsequent heat treatment under ammonia. By adjusting the proportion the of pre oxidation of CNTs and precursor CoWO4 and ammonia heat treatment temperature, the Co3W3N in uniform load on the surface of the CNTs. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) test results showed that the catalyst particles evenly dispersed on the surface of CNTs, due to oxidation CNTs for the good dispersion growth of precursor. The Co3W3N particle size on the CNTs was about 20 nm, which was significantly smaller than that of unsupported Co3W3N (100 nm). The electrochemical tests was carried out in a N2 saturated 0.01 mol·L-1 H2SO4 solution under different potential, and the material achieved the highest ammonia production rate and Faraday efficiency at -0.3 V, which reached approximately 12.73 μg·h-1·cm-2 and 13.59%, respectively. Under the same conditions, the ammonia production rate and Faraday efficiency of pure phase Co3W3N were only 1.08 μg·h-1·cm-2 and 1.76%. The Co3W3N/CNTs sample showed excellent NRR (nitrogen reduction reaction) performance because of the Co3W3N as the active site and the synergistic effect of Co3W3N and CNTs.
2020, 36(3): 475-484
doi: 10.11862/CJIC.2020.052
Abstract:
The photocatalytic activity of in situ sulfur-doped g-C3N4 was improved by simple and green ball milling using thiourea as raw material. Its structure and optical properties were characterized by X-ray diffraction, scanning electron microscope, elemental analysis, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. The visible light photocatalytic performance of ball milled sulfur-doped g-C3N4 photocatalyst at different solvent ratios was evaluated with methylene blue as the target pollutant. The results show that the specific surface area and the number of reactive sites of the sulfur-doped g-C3N4 photocatalyst after wet ball milling are increased, and the band gap also increased appropriately, resulting in enhanced redox capacity. In addition, the surface defects of the sample after wet ball milling were reduced and the degree of polymerization was increased, which promoted the effective separation and transfer of photogenerated electron-holes. Therefore, the recombination rate can be lowered, and the degradation performance of the sulfur-doped g-C3N4 photocatalyst improved synergistically. The degradation rate of methylene blue in the wet ball milled sample was 1.5 and 3.6 times higher than that of the without ball milled sample and the dry ball milled sample, respectively.
The photocatalytic activity of in situ sulfur-doped g-C3N4 was improved by simple and green ball milling using thiourea as raw material. Its structure and optical properties were characterized by X-ray diffraction, scanning electron microscope, elemental analysis, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. The visible light photocatalytic performance of ball milled sulfur-doped g-C3N4 photocatalyst at different solvent ratios was evaluated with methylene blue as the target pollutant. The results show that the specific surface area and the number of reactive sites of the sulfur-doped g-C3N4 photocatalyst after wet ball milling are increased, and the band gap also increased appropriately, resulting in enhanced redox capacity. In addition, the surface defects of the sample after wet ball milling were reduced and the degree of polymerization was increased, which promoted the effective separation and transfer of photogenerated electron-holes. Therefore, the recombination rate can be lowered, and the degradation performance of the sulfur-doped g-C3N4 photocatalyst improved synergistically. The degradation rate of methylene blue in the wet ball milled sample was 1.5 and 3.6 times higher than that of the without ball milled sample and the dry ball milled sample, respectively.
2020, 36(3): 485-493
doi: 10.11862/CJIC.2020.060
Abstract:
We synthesized self-supported Ni-based MOF material on nickel foam (Ni-MOF/NF) with high mass loading vis a one-step hydrothermal method by the use of nickel chloride as a metal salt and terephthalic acid (PTA) as an organic ligand. Solvents had a remarkable effect on the morphology and electrochemical performance of the Ni-MOF/NF because of the different pH values and solubility of PTA. The higher the solubility of the solvent and pH value was, the faster the diproton rate of PTA in the solution and the nucleation rate. As a result, self-supported Ni-based MOF material exhibited different morphologies such as spherical cluster, flake and bulk, resulting in an increasing mass loading of Ni-based MOFs on the Ni foam. When using a ternary mixture (N, N-dimethylformamide, water and ethanol with volume ratio of 1:1:1) solvent, Ni-MOF/NF achieved the highest loading mass of 10 mg·cm-2 and the area capacity of 8 780 mF·cm-2 at a current density of 1 mA·cm-2 in 3 mol·L-1 KOH electrolyte. Even at high current density of 5 mA·cm-2, the area capacity still reached at 5 544 mF·cm-2 and the capacity retention rate was 63%, delivering an excellent rate performance. Furthermore, the area capacity retention rate was 56% after 1 000 cycles.
We synthesized self-supported Ni-based MOF material on nickel foam (Ni-MOF/NF) with high mass loading vis a one-step hydrothermal method by the use of nickel chloride as a metal salt and terephthalic acid (PTA) as an organic ligand. Solvents had a remarkable effect on the morphology and electrochemical performance of the Ni-MOF/NF because of the different pH values and solubility of PTA. The higher the solubility of the solvent and pH value was, the faster the diproton rate of PTA in the solution and the nucleation rate. As a result, self-supported Ni-based MOF material exhibited different morphologies such as spherical cluster, flake and bulk, resulting in an increasing mass loading of Ni-based MOFs on the Ni foam. When using a ternary mixture (N, N-dimethylformamide, water and ethanol with volume ratio of 1:1:1) solvent, Ni-MOF/NF achieved the highest loading mass of 10 mg·cm-2 and the area capacity of 8 780 mF·cm-2 at a current density of 1 mA·cm-2 in 3 mol·L-1 KOH electrolyte. Even at high current density of 5 mA·cm-2, the area capacity still reached at 5 544 mF·cm-2 and the capacity retention rate was 63%, delivering an excellent rate performance. Furthermore, the area capacity retention rate was 56% after 1 000 cycles.
2020, 36(3): 494-502
doi: 10.11862/CJIC.2020.045
Abstract:
A cyclometalated iridium(Ⅲ) complex Ir(tpit)(sb)Cl (tpitH2=triphenyl phosphite) containing 4, 5-diazo-9, 9-spirobifluorene (sb) ligand was successfully synthesized and characterized by NMR spectroscopy and high resolution mass spectrometry. X-ray single crystal diffraction analysis showed that the existence of sb ligand distorted the structure of complex, which is beneficial for reducing the molecular aggregation and luminescent quenching. The photoelectric properties of complex Ir(tpit)(sb)Cl has been studied in comparison with those of the model complex Ir(tpit)(bpy)Cl (bpy=2, 2'-bipyridine) existing intramolecular π-π stacking. The results show that the luminescence wavelength of complex Ir(tpit)(sb)Cl in polymethyl methacrylate (mass fraction 1%) was 512 nm, and had a blue shift of 8 nm compared to that of complex Ir(tpit)(bpy)Cl (520 nm). The quantum efficiency of the complex Ir(tpit)(sb)Cl was 30%, which is significantly lower than that of the complex Ir(tpit)(bpy)Cl (94%), indicating the radiative transition rate is reduced by spirofluorene. Based on the complex Ir(tpit)(sb)Cl, the maximum current efficiency and external quantum efficiency of OLED device are 14 cd·A-1 and 4.5%, respectively. The maximum current efficiency and external quantum efficiency of Ir(tpit)(bpy)Cl-based device are up to 60 cd·A-1 and 18.2%, respectively.
A cyclometalated iridium(Ⅲ) complex Ir(tpit)(sb)Cl (tpitH2=triphenyl phosphite) containing 4, 5-diazo-9, 9-spirobifluorene (sb) ligand was successfully synthesized and characterized by NMR spectroscopy and high resolution mass spectrometry. X-ray single crystal diffraction analysis showed that the existence of sb ligand distorted the structure of complex, which is beneficial for reducing the molecular aggregation and luminescent quenching. The photoelectric properties of complex Ir(tpit)(sb)Cl has been studied in comparison with those of the model complex Ir(tpit)(bpy)Cl (bpy=2, 2'-bipyridine) existing intramolecular π-π stacking. The results show that the luminescence wavelength of complex Ir(tpit)(sb)Cl in polymethyl methacrylate (mass fraction 1%) was 512 nm, and had a blue shift of 8 nm compared to that of complex Ir(tpit)(bpy)Cl (520 nm). The quantum efficiency of the complex Ir(tpit)(sb)Cl was 30%, which is significantly lower than that of the complex Ir(tpit)(bpy)Cl (94%), indicating the radiative transition rate is reduced by spirofluorene. Based on the complex Ir(tpit)(sb)Cl, the maximum current efficiency and external quantum efficiency of OLED device are 14 cd·A-1 and 4.5%, respectively. The maximum current efficiency and external quantum efficiency of Ir(tpit)(bpy)Cl-based device are up to 60 cd·A-1 and 18.2%, respectively.
2020, 36(3): 503-514
doi: 10.11862/CJIC.2020.056
Abstract:
Dinuclear Ni(Ⅱ) and cubane-like Cu4(μ3-O)4 cored tetranuclear Cu(Ⅱ) complexes, [Ni(L1)(DMF)(H2O)]2 (1) (H2L1=3-((5-bromo-2-hydroxy-benzylidene)-amino)-4-hydroxy-benzopyran-2-one), [Cu4(L2)4]·DMF·CH3OH·2H2O (2) (H2L2=4-hydroxy-3-((2-hydroxy-3-methoxy-benzylidene)-amino)-benzopyran-2-one) based on 3-amino-4-hydroxy-coumarin Schiff base ligands were synthesized and characterized by elemental analysis, IR, UV-Vis, emission spectra and X-ray single crystal diffraction analysis. The X-ray single crystal diffraction analysis results show that complex 1 has a binuclear structure composed of two metal ions and two ligand units, and complex 2 has a tetranuclear structure composed of four metal ions and four ligand units. Complex 1 crystallizes in monoclinic system, C2/c space group, whereas complex 2 crystallizes in tetragonal system, I41/a space group. The spatial configurations of the central metal Ni(Ⅱ) and Cu(Ⅱ) ions are all six-coordinated distorted octahedron in complexes 1 and 2, respectively. In addition, complex 1 forms a one-dimensional (1D) supramolecular chain through intermolecular hydrogen bonding, C-H…π and π…π stacking interactions, while complex 2 formed three-dimensional(3D) supramolecular network structure via intramolecular hydrogen bonding and π…π stacking interactions.
Dinuclear Ni(Ⅱ) and cubane-like Cu4(μ3-O)4 cored tetranuclear Cu(Ⅱ) complexes, [Ni(L1)(DMF)(H2O)]2 (1) (H2L1=3-((5-bromo-2-hydroxy-benzylidene)-amino)-4-hydroxy-benzopyran-2-one), [Cu4(L2)4]·DMF·CH3OH·2H2O (2) (H2L2=4-hydroxy-3-((2-hydroxy-3-methoxy-benzylidene)-amino)-benzopyran-2-one) based on 3-amino-4-hydroxy-coumarin Schiff base ligands were synthesized and characterized by elemental analysis, IR, UV-Vis, emission spectra and X-ray single crystal diffraction analysis. The X-ray single crystal diffraction analysis results show that complex 1 has a binuclear structure composed of two metal ions and two ligand units, and complex 2 has a tetranuclear structure composed of four metal ions and four ligand units. Complex 1 crystallizes in monoclinic system, C2/c space group, whereas complex 2 crystallizes in tetragonal system, I41/a space group. The spatial configurations of the central metal Ni(Ⅱ) and Cu(Ⅱ) ions are all six-coordinated distorted octahedron in complexes 1 and 2, respectively. In addition, complex 1 forms a one-dimensional (1D) supramolecular chain through intermolecular hydrogen bonding, C-H…π and π…π stacking interactions, while complex 2 formed three-dimensional(3D) supramolecular network structure via intramolecular hydrogen bonding and π…π stacking interactions.
Synthesis, Crystal Structure, and Antibacterial Activity of Copper(Ⅱ) Complexes Based on Norfloxacin
2020, 36(3): 515-520
doi: 10.11862/CJIC.2020.054
Abstract:
Two copper complexes[Cu2(HNOR)2Cl]n (1) and[Cu2Cl3]·H3NOR·H2O (2) (H2NOR=norfloxacin) were prepared by hydrothermal process and their structures were determined by single-crystal X-ray diffraction. The results showed that although the reactants are the same, the complexes with different structures are formed under acidic and basic conditions. Through the hydrogen bonding interactions and π-π interactions, two complexes form stable two-dimensional structure. At the same time, Escherichia coli and Staphylococcus aureus were selected as Gram positive and Gram negative for antibacterial activity experiments. Bacteriostatic activity showed that both complexes had a good inhibitory effect on Escherichia coli and Staphylococcus aureus.
Two copper complexes[Cu2(HNOR)2Cl]n (1) and[Cu2Cl3]·H3NOR·H2O (2) (H2NOR=norfloxacin) were prepared by hydrothermal process and their structures were determined by single-crystal X-ray diffraction. The results showed that although the reactants are the same, the complexes with different structures are formed under acidic and basic conditions. Through the hydrogen bonding interactions and π-π interactions, two complexes form stable two-dimensional structure. At the same time, Escherichia coli and Staphylococcus aureus were selected as Gram positive and Gram negative for antibacterial activity experiments. Bacteriostatic activity showed that both complexes had a good inhibitory effect on Escherichia coli and Staphylococcus aureus.
2020, 36(3): 521-528
doi: 10.11862/CJIC.2020.067
Abstract:
High-purity hydroxyapatite (HAP) was prepared from oyster-shell waste by a hydrothermal method and was used as the carrier for Ag3PO4, resulting in the preparation of a nanorod-like Ag3PO4/HAP composite photocatalyst. Scanning electron microscopy (SEM), high-resolution transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared photocatalyst and to explore the effect of different preparation parameters on the catalytic activity of the photocatalyst toward the degradation of a methylene blue solution. The results shows that the 1:2-Ag3PO4/HAP catalyst exhibited the best performance, achieving 50% degradation in 10 min and complete degradation in 40 min. The 1:2-Ag3PO4/HAP catalyst was a highly efficient composite photocatalyst.
High-purity hydroxyapatite (HAP) was prepared from oyster-shell waste by a hydrothermal method and was used as the carrier for Ag3PO4, resulting in the preparation of a nanorod-like Ag3PO4/HAP composite photocatalyst. Scanning electron microscopy (SEM), high-resolution transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared photocatalyst and to explore the effect of different preparation parameters on the catalytic activity of the photocatalyst toward the degradation of a methylene blue solution. The results shows that the 1:2-Ag3PO4/HAP catalyst exhibited the best performance, achieving 50% degradation in 10 min and complete degradation in 40 min. The 1:2-Ag3PO4/HAP catalyst was a highly efficient composite photocatalyst.
2020, 36(3): 529-535
doi: 10.11862/CJIC.2020.046
Abstract:
Treatment of H3pdc with Zn(NO3)2·6H2O under different reaction conditions afforded two complexes, [Zn(H2pdc)2(H2O)2]·2H2O (1) and[Zn2(Hpdc)2(H2O)6]·2H2O (2) (H3pdc=3, 4-pyrazoledicarboxylic acid). X-ray diffraction analyses reveal that 1 and 2 contain mono-and dinuclear Zn(Ⅱ) components, respectively. The partly deprotonated H3pdc ligand anions in 1 and 2 adopt N, O-chelating fashion (H2pdc-) and μ2-κN, O:κN' bridging mode (Hpdc2-), respectively. In both complexes, the adjacent zero-dimensional components are connected by intermolecular hydrogen bonds (O-H…O, N-H…O and C-H…O) to form a three-dimensional supramolecular architecture. The thermal and luminescent properties of complexes 1 and 2 have also been investigated.
Treatment of H3pdc with Zn(NO3)2·6H2O under different reaction conditions afforded two complexes, [Zn(H2pdc)2(H2O)2]·2H2O (1) and[Zn2(Hpdc)2(H2O)6]·2H2O (2) (H3pdc=3, 4-pyrazoledicarboxylic acid). X-ray diffraction analyses reveal that 1 and 2 contain mono-and dinuclear Zn(Ⅱ) components, respectively. The partly deprotonated H3pdc ligand anions in 1 and 2 adopt N, O-chelating fashion (H2pdc-) and μ2-κN, O:κN' bridging mode (Hpdc2-), respectively. In both complexes, the adjacent zero-dimensional components are connected by intermolecular hydrogen bonds (O-H…O, N-H…O and C-H…O) to form a three-dimensional supramolecular architecture. The thermal and luminescent properties of complexes 1 and 2 have also been investigated.
2020, 36(3): 536-546
doi: 10.11862/CJIC.2020.038
Abstract:
Spinel Li1.6Mn1.6O4 was synthesized by hydrothermal oxidation of MnSO4 with KMnO4 to form LiMnO2 following solid-phase roasting. Acid pickling transforms Li1.6Mn1.6O4 to lithium ion-sieve. The effects of hydrothermal temperature, oxygen and molar ratio of MnO4- to Mn2+ (nMnO4-:nMn2+) on LiMnO2 composition and the dissolution percentage of manganese from Li1.6Mn1.6O4 during acid pickling were investigated. Open circuit potential measurement and chemical analysis indicate that oxygen in the air has involved in the hydrothermal reaction to produce LiMnO2 accompanied by formation of Li2MnO3 and LiMn2O4 impurities at a theoretical nMnO4-:nMn2+ of 1:4. Pure orthogonal LiMnO2 (o-LiMnO2) was obtained with a molar ratio of MnO4-to Mn2+ of 1:6 at 160℃. The Li+ adsorption capacity in salt lake brine was 42.87 mg·g-1. The lithium ion-sieve showed excellent adsorption selectivity toward Li+ in salt lake brine and followed a chemical adsorption process. The adsorption capacity remained at 37.21 mg·g-1 and the dissolution percentage of manganese decreased to 0.34% after 5 cycles.
Spinel Li1.6Mn1.6O4 was synthesized by hydrothermal oxidation of MnSO4 with KMnO4 to form LiMnO2 following solid-phase roasting. Acid pickling transforms Li1.6Mn1.6O4 to lithium ion-sieve. The effects of hydrothermal temperature, oxygen and molar ratio of MnO4- to Mn2+ (nMnO4-:nMn2+) on LiMnO2 composition and the dissolution percentage of manganese from Li1.6Mn1.6O4 during acid pickling were investigated. Open circuit potential measurement and chemical analysis indicate that oxygen in the air has involved in the hydrothermal reaction to produce LiMnO2 accompanied by formation of Li2MnO3 and LiMn2O4 impurities at a theoretical nMnO4-:nMn2+ of 1:4. Pure orthogonal LiMnO2 (o-LiMnO2) was obtained with a molar ratio of MnO4-to Mn2+ of 1:6 at 160℃. The Li+ adsorption capacity in salt lake brine was 42.87 mg·g-1. The lithium ion-sieve showed excellent adsorption selectivity toward Li+ in salt lake brine and followed a chemical adsorption process. The adsorption capacity remained at 37.21 mg·g-1 and the dissolution percentage of manganese decreased to 0.34% after 5 cycles.
2020, 36(3): 547-554
doi: 10.11862/CJIC.2020.036
Abstract:
This work focuses on Strecker reactions catalyzed by metal-organic framework (MOF) of amino-functionalized Ga-MIL-53 (NH2-Ga-MIL-53) in regard to substrates of a series of N-Ph aldimines, and the results showed that:(1) NH2-Ga-MIL-53 exhibited excellect catalytic activity and good univisality among various substrates; (2) the electronic effect of substituents for substrates primarily affects the catalytic reaction rate, and the electron-donating substituted groups (i.e., MeO, Ph) and electron-withdrawing substituted groups (i.e., CF3, NO2) show promotion and suppression effects on the reaction, respectively; (3) the substituted position of substituents in respect of substrates secondarily influences the reaction rate, and the ortho-substituted MeO group perform the strongest promotion effects on the reaction; (4) as a heterogeneous catalyst, NH2-Ga-MIL-53 can be reused for 9 runs without obvious loss of conversion efficiencies and collapse of MOF structure; (5) contrasting the catalytic performances between NH2-Ga-MIL-53 and Ga-MIL-53, it is indicated that the amino groups of NH2-Ga-MIL-53 can be served as Lewis base moieties, facilating the reaction according to Lewis acid-base synergistic mechanism. Furthermore, comparing the catalytic effects among NH2-Ga-MIL-53, Ga(NO3)3·6H2O and 2-aminoterephthalic acid, it is concluded that the pore structure of NH2-Ga-MIL-53 framework plays a significant role in avoiding the side reactions with respect to Strecker reaction.
This work focuses on Strecker reactions catalyzed by metal-organic framework (MOF) of amino-functionalized Ga-MIL-53 (NH2-Ga-MIL-53) in regard to substrates of a series of N-Ph aldimines, and the results showed that:(1) NH2-Ga-MIL-53 exhibited excellect catalytic activity and good univisality among various substrates; (2) the electronic effect of substituents for substrates primarily affects the catalytic reaction rate, and the electron-donating substituted groups (i.e., MeO, Ph) and electron-withdrawing substituted groups (i.e., CF3, NO2) show promotion and suppression effects on the reaction, respectively; (3) the substituted position of substituents in respect of substrates secondarily influences the reaction rate, and the ortho-substituted MeO group perform the strongest promotion effects on the reaction; (4) as a heterogeneous catalyst, NH2-Ga-MIL-53 can be reused for 9 runs without obvious loss of conversion efficiencies and collapse of MOF structure; (5) contrasting the catalytic performances between NH2-Ga-MIL-53 and Ga-MIL-53, it is indicated that the amino groups of NH2-Ga-MIL-53 can be served as Lewis base moieties, facilating the reaction according to Lewis acid-base synergistic mechanism. Furthermore, comparing the catalytic effects among NH2-Ga-MIL-53, Ga(NO3)3·6H2O and 2-aminoterephthalic acid, it is concluded that the pore structure of NH2-Ga-MIL-53 framework plays a significant role in avoiding the side reactions with respect to Strecker reaction.
2020, 36(3): 555-565
doi: 10.11862/CJIC.2020.059
Abstract:
A highly activated polyporous silver film was constructed on the outer ring of silver wire by voltammetric etching using halogen anions. In particular, chloride ion etching can promote the formation of self-supported porous channel structure on silver wire surface via microcell reactions. Appling a continuous positive potential to the silver wire electrode contributes to form a thin film of AgCl. After electrochemical reduction, chloride ions are stripped from AgCl and the AgCl spontaneously transformed to self-supported polyporous silver film. The as prepared self-supported polyporous silver film electrode (p-Ag film) reveals substantial electrocatalytic activity for the selective and sensitive sensing of trichloroacetic acid. The p-Ag film electrode displays 174 and 3.7 times enhancement in electrochemical active surface area and the dechlorination reaction, relative to the pristine silver wire electrode (r-Ag wire). The novel electrodes exhibited a low detection limit of 70 nmol·L-1 (fitting correlation coefficient R2=0.998 3) with the trichloroacetic acid concentration range of 0.1~518.1 μmol·L-1.
A highly activated polyporous silver film was constructed on the outer ring of silver wire by voltammetric etching using halogen anions. In particular, chloride ion etching can promote the formation of self-supported porous channel structure on silver wire surface via microcell reactions. Appling a continuous positive potential to the silver wire electrode contributes to form a thin film of AgCl. After electrochemical reduction, chloride ions are stripped from AgCl and the AgCl spontaneously transformed to self-supported polyporous silver film. The as prepared self-supported polyporous silver film electrode (p-Ag film) reveals substantial electrocatalytic activity for the selective and sensitive sensing of trichloroacetic acid. The p-Ag film electrode displays 174 and 3.7 times enhancement in electrochemical active surface area and the dechlorination reaction, relative to the pristine silver wire electrode (r-Ag wire). The novel electrodes exhibited a low detection limit of 70 nmol·L-1 (fitting correlation coefficient R2=0.998 3) with the trichloroacetic acid concentration range of 0.1~518.1 μmol·L-1.
2020, 36(3): 566-574
doi: 10.11862/CJIC.2020.055
Abstract:
g-C3N4/Ag/TiO2 ternary photocatalysts were successfully constructed by a mechanical agitation method with as-synthesized Ag/TiO2 hollow microspheres and g-C3N4 nanosheets as the raw materials. The photocatalysts were systematically characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), and photoluminescence spectra (PL). The results showed that g-C3N4/Ag/TiO2 was assembled by Ag/TiO2 microspheres and g-C3N4 nanosheets. Compared with TiO2, the resultant g-C3N4/Ag/TiO2 heterojunctions possessed longer visible-light response range and faster photo-induced carrier separation rate. At room temperature, the visible-light photocatalytic activity of g-C3N4/Ag/TiO2 was investigated by photodegradation of rhodamine B (RhB). The results showed that the highest visible-light-driven photocatalytic efficiency of g-C3N4 (0.5%)/Ag/TiO2 with 180 min of light irradiation was 91.9%, which was nearly 7.5 and 1.8 times higher than pure TiO2 and two-component Ag/TiO2, respectively. The enhanced photocatalytic activity could be mainly attributed to the reasonably designed heterojunctions and the electrical conductivity of Ag.
g-C3N4/Ag/TiO2 ternary photocatalysts were successfully constructed by a mechanical agitation method with as-synthesized Ag/TiO2 hollow microspheres and g-C3N4 nanosheets as the raw materials. The photocatalysts were systematically characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), and photoluminescence spectra (PL). The results showed that g-C3N4/Ag/TiO2 was assembled by Ag/TiO2 microspheres and g-C3N4 nanosheets. Compared with TiO2, the resultant g-C3N4/Ag/TiO2 heterojunctions possessed longer visible-light response range and faster photo-induced carrier separation rate. At room temperature, the visible-light photocatalytic activity of g-C3N4/Ag/TiO2 was investigated by photodegradation of rhodamine B (RhB). The results showed that the highest visible-light-driven photocatalytic efficiency of g-C3N4 (0.5%)/Ag/TiO2 with 180 min of light irradiation was 91.9%, which was nearly 7.5 and 1.8 times higher than pure TiO2 and two-component Ag/TiO2, respectively. The enhanced photocatalytic activity could be mainly attributed to the reasonably designed heterojunctions and the electrical conductivity of Ag.
2020, 36(3): 575-583
doi: 10.11862/CJIC.2020.051
Abstract:
The V2O5 hollow spheres were used as a high efficient sulfur host for Li-S batteries, which was used for the storage of sulfur and restricting the shuttle effect of polysulfides. The hollow spheres had an average diameter around 500 nm, providing more space for storing sulfur, accommodating volumetric change of sulfur electrode. At the same time, V2O5 has a strong chemical adsorption of polysulfides, which can effectively limit the shuttle effect of polysulfides. The high capacity and excellent stability of Li-S batteries have been realized simultaneously due to the increasing of the storage of sulfur by the hollow structure and strong chemical adsorption for polysulfides by chemical bonding. The Li-S batteries with as-prepared V2O5/S cathode showed a high reversible capacity of 1 439 mAh·g-1 at 0.1C and stable cycling performance with a capacity of~600 mAh·g-1 after 300 cycles at 1C.
The V2O5 hollow spheres were used as a high efficient sulfur host for Li-S batteries, which was used for the storage of sulfur and restricting the shuttle effect of polysulfides. The hollow spheres had an average diameter around 500 nm, providing more space for storing sulfur, accommodating volumetric change of sulfur electrode. At the same time, V2O5 has a strong chemical adsorption of polysulfides, which can effectively limit the shuttle effect of polysulfides. The high capacity and excellent stability of Li-S batteries have been realized simultaneously due to the increasing of the storage of sulfur by the hollow structure and strong chemical adsorption for polysulfides by chemical bonding. The Li-S batteries with as-prepared V2O5/S cathode showed a high reversible capacity of 1 439 mAh·g-1 at 0.1C and stable cycling performance with a capacity of~600 mAh·g-1 after 300 cycles at 1C.
